If you want a fairly budget deck for grinding your way into Mythic, then monored is the way to go. As a highly competitive aggro deck, the games go pretty fast. The deck focuses on two busted cards: Runaway Steam-Kin and Experimental Frenzy.
How these cards are busted
Runaway eventually turns into a 4/4 creature for only 2 mana. This is fairly efficient. However, its fast mana is what really pushes it over the edge: you sort of get 1 red mana every time you cast a red spell. If you have 2 Runaways, then you can “get” 2 red mana for casting a 1-cost red spell. This creature can let you generate huge amounts of mana on one turn and really go off.
Experimental Frenzy is a card advantage engine that often lets you get multiple cards per turn. If the enchantment is allowed to sit for a few turns before being answered, then you can start playing the cards in your hand and burn the opponent’s life total to 0. Or, if you have enough points of burn damage in your hand, you can destroy the enchantment and finish off your opponent.
While this deck runs plenty of bad cards, Experiment Frenzy allows you to ignore that by using quantity over quality to finish off your opponent’s life total. Frenzy is a pretty good finisher, although you are always gambling on the outcome. Sometimes the monored gods will not shine upon you and brick you with lands or another Experimental Frenzy on top of the deck.
19 Mountain (RIX) 195
4 Experimental Frenzy (GRN) 99
4 Ghitu Lavarunner (DAR) 127
4 Viashino Pyromancer (M19) 166
1 Burning Prophet (WAR) 117
4 Wizard’s Lightning (DAR) 152
4 Light Up the Stage (RNA) 107
4 Fanatical Firebrand (RIX) 101
3 Goblin Chainwhirler (DAR) 129
4 Shock (M19) 156
4 Lightning Strike (M19) 152
4 Runaway Steam-Kin (GRN) 115
1 Chandra, Fire Artisan (WAR) 119
Fanatical Firebrand and Ghitu Lavarunner: Run 4 copies of each because they cost 1 red mana and are reasonably efficient creatures. They generally do a little more damage to the opponent than Shock would.
Finishers – Experimental Frenzy and Chandra, Fire Artisan: You’ll want 3-4 copies of Experiment Frenzy, so craft at least 3. Chandra is a fine finisher because she is hard to deal with. She has some synergy with Experimental Frenzy as her ability can remove bricks from the top of your deck. Play lands first, and then use her ability to remove the second land that you see in a turn.
Other finishers include a second Chandra and Rekindling Phoenix. Risk Factor is ok, but it is a total nonbo with Experimental Frenzy. 4-5 finishers is about right.
Viashino Pyromancer: It’s a cheap somewhat efficient creature. Because it’s a wizard, it reduces the cost on Wizard’s Lightning. This is helpful because 1 mana red spells allow you to really go off with Steamkin.
Burning Prophet: This is a spicy 1-of that synergizes somewhat with Experimental Frenzy, allowing you to unbrick yourself. Whenever you don’t have Frenzy, it helps you dig for it and lands.
Goblin Chainwhirler: This card is great against monored, monowhite, and decks that play Llanowar Elves and Paradise Druid. Running 4 may be a good idea if you run into those decks most of the time. The goblin is not that great elsewhere. If you don’t have this rare, then replacements could include: Rekindling Phoenix, Burning Prophet, Krenkto Tin Street Kingpin, Legion Warboss, Skarrgan Hellkite, Skewer the Critics.
Skewer the Critics: I don’t run any copies of this card, but it works in monored. Wizard’s Lightning is better because it is more likely to cost only 1 (and it’s instant speed).
Light Up the Stage: Definitely run 4 of these. It’s card advantage, it cycles itself (kind of), and it often costs only 1 to cast to allow you to really go off with Steamkin. Be aware that if you play it on turn 2, you may flip Experimental Frenzy and be unable to cast it (unless you have Steamkin with counters on it). In longer matchups, you may want to hold off until you have 3 lands in play.
Shock: This isn’t a great card when we already run 4 Fanatical Firebrands to take out elves, but we run this anyways because it costs 1 red.
Lightning Strike: It’s fine. Nothing exciting.
Mountains: Anywhere from 18 to 22 is probably right.
The minimum that you want to craft are the commons, uncommons, 4 Steam-Kins, 1 Goblin Chainwhirler, and 3 Experimental Frenzies.
Piloting the deck (basics)
Sacrifice your creatures
Suppose that attacking would cause you to lose a creature but deal 3 damage to the opponent. Most of the time, this is a good trade. It’s like you turned your creature into a Lightning Strike that you didn’t have to pay mana for. Because this deck is all about getting the opponent’s life total to 0, you end up using a lot of your burn spells on the opponent directly anyways.
In many situations, you should sacrifice your creatures to get your opponent’s life total in a dangerous range. If you attack with all of your creatures again and your opponent’s life total would end up at 3, they are in a very dangerous place because many of your burn spells do 3 damage.
Always calculate lethal
Always check to see if attacking the opponent with your creatures and using all of your burn spells on the opponent would put them to 0 or close to it. If you can kill them on your turn, you should do it so that they can’t draw a card that turns the game around.
If Goblin Chainwhirler is in your hand, think about the Chainwhirler’s 1 damage effect on clearing out blockers and “burning” the opponent for 1 damage.
Face is the place
In many but not all cases, you want to ignore the opponent’s creatures and send burn spells to their face to put them at a precarious life total.
Most games go pretty fast, sometimes securing a concession by turn 5. However, in other games, things may look bad for you but resolving an Experimental Frenzy may win you the game. So you often want to stick around in the hope that you draw your out. Overall, monored is one of the best decks to ladder with because it is highly competitive in the current metagame and it results in the shortest games. It also happens to be extremely budget friendly.
If you want to get to Mythic for the sake of achieving it, monored is the way to go.